Revert r191586 and r191695. They cause crashes when building with
-relaxed-aliasing.

llvm-svn: 191725
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 93571ff..dd48bc1 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -2183,9 +2183,8 @@
                     options::OPT_fno_strict_aliasing,
                     getToolChain().IsStrictAliasingDefault()))
     CmdArgs.push_back("-relaxed-aliasing");
-  if (!Args.hasFlag(options::OPT_fstruct_path_tbaa,
-                    options::OPT_fno_struct_path_tbaa))
-    CmdArgs.push_back("-no-struct-path-tbaa");
+  if (Args.hasArg(options::OPT_fstruct_path_tbaa))
+    CmdArgs.push_back("-struct-path-tbaa");
   if (Args.hasFlag(options::OPT_fstrict_enums, options::OPT_fno_strict_enums,
                    false))
     CmdArgs.push_back("-fstrict-enums");